Hydraulically actuated and solenoid operated directional valves are known in the art. These valves may have detent means that make direct contact either with the spool or with a pin that actuates the spool, and the detent means functions thereby to hold the spool in a selected position.
To provide holding engagement by the detent means a variety of constructions and arrangements have been utilized, as is described in U.S. Pat. No. 4,185,661, patented Jan. 29, 1980 in the names of Gill et al. The cited patent discloses a detent means that is an improvement over earlier prior art apparatus, and there remains a need for further improvements in the art. In the cited patent, the detent means includes a C-shaped spring that partially encircles a pair of split sleeves that are in engagement with the solenoid pin for holding the latter. To assure a uniform disengagement force of the detent means, it is necessary to provide a precision C-shaped spring which may be costly to manufacture. Further, because the C-shaped spring may shift its position in a circumferential direction, that is, by rotating relative to the split sleeves, it is possible that the disengagement force required may vary in an undesirable manner if the gap of the C-shaped spring aligns itself with the parting plane between the split sleeves. Thus, while the detent means of the cited patent has overcome inadequacies of the prior art, improvements from the standpoint of cost and performance in use are still required.